1. Field of the Invention
This invention relates to vehicles for delivering of liquids to a storage location, and more particularly, to a liquid delivery vehicle having a liquid delivery system which is at least partially remotely controllable.
2. Description of the Prior Art
There are many applications for the transportation of liquids by a ground vehicle for delivery to a storage location. The design and construction of such vehicles, and of the liquid delivery systems on those vehicles, vary depending upon the type of liquid being transported and delivered. In many cases, rules and regulations, both state and federal, such as United States Department of Transportation regulations, apply to the vehicles and to the delivery of liquids therefrom.
Volatile and flammable liquids, such as liquefied petroleum gases (LP gas or LPG), require very specialized equipment and careful handling. Liquefied petroleum gases, such as butane and propane, must be maintained under pressure at ambient temperatures to keep them in a liquid state. These liquids are extremely volatile; they will boil unless maintained under pressure. For example, propane boils at -44.degree. F., and butane boils at +31.degree. F. That is, butane and propane exist only in a gaseous state at atmospheric pressure and most ambient temperatures. In order to keep liquefied petroleum gases in a pressurized, liquid state, they must be stored in pressure vessels capable of withstanding internal pressures greater than atmospheric pressure.
Delivery vehicles for transporting and delivering liquefied petroleum gases must therefore have a pressurized tank or vessel thereon to hold the LP gas in a liquid state, and when the LP gas is delivered, it must be transferred into a similar pressurized storage tank or vessel. All of the interconnecting equipment and piping must also be designed to withstand these high internal pressures. The present invention is designed specifically to be used in an LP gas transport and delivery system, although the main components and principles of operation would also be applicable to the delivery of other liquids, including non-volatile liquids.
LP gas delivery vehicles are well known in the art, and are frequently used to deliver liquefied petroleum gas to storage vessels, particularly in rural areas. LP gases are flammable, and thus useful as fuels, and typically delivery vehicles are used to deliver the LP gas to residential storage tanks and also to larger commercial storage vessels from which the LP gas may be further distributed. LP gases are used for commercial and residential heating, motor fuels, and other applications such as heating, cooling and cooking on recreational vehicles.
In a typical LP gas delivery cycle, the driver/operator parks the vehicle at some distance spaced from the storage vessel or tank to be filled. It may be possible to park the vehicle immediately adjacent to the storage tank, but in most cases, this is not possible. Regardless of the distance, however, the general procedure for filling the storage tank is the same.
After parking the vehicle, the operator chocks the wheels so that unintended movement of the vehicle is prevented, after which the actual delivery cycle may be carried out.
These delivery vehicles typically have a flow meter, and the operator inserts a ticket into the meter which records the transaction so that the customer can be billed the appropriate amount for the volume of liquid delivered to the customer's storage tank. The operator then takes or "acquires" a delivery hose attached to the vehicle and extends the hose from the vehicle to the storage tank. A hose valve is disposed on the end of the hose along with a coupling. The coupling is attached to a mating fitting on the tank, and the hose valve is opened. The operator then returns to the delivery truck.
Back at the truck, the operator actuates control levers to open an internal flow valve on the truck which allows fluid communication between the delivery tank and a liquid transferring means, such as a pump. The operator then disengages the clutch on the vehicle, assuming the vehicle has a manual transmission, and while the clutch is disengaged, engages a power take-off. For vehicles with automatic transmissions, a control solenoid on the power take-off is actuated. The power take-off is connected to a shaft of the pump. Once the power take-off is engaged, the clutch is reengaged to allow power from the engine to drive the pump through the power take-off.
The operator then returns to the storage tank and observes the liquid fuel level on a liquid level gauge at the tank. Just before the fluid level reaches the maximum allowable amount, the driver again returns to the truck from the storage tank and stops the pump. This procedure includes disengaging the clutch and then disengaging the power takeoff. The internal flow valve in the delivery tank can then be closed.
The operator again returns to the storage tank, closes the hose valve, and disconnects the hose from the storage tank. The hose is then rewound onto its reel. At this point, the vehicle can then be driven to another location for filling another storage tank.
In this prior art procedure, three round trips by the operator from the delivery vehicle to the storage tank are required. Also, since the operator has to leave the storage tank before it is full, the amount of fluid pumped into the storage tank is only an estimate at the time the operator disengages the pump. Thus, it is possible that the storage vessel will not be completely filled. This presents a disadvantage to the provider of the LP gas of not selling as much as possible and also provides the disadvantage to the customer of not having the tank completely filled which may necessitate a shorter time between deliveries or possibly result in the customer running out of fuel. If the tank is overfilled, it may present a safety hazard.
Thus, there is a need to provide more accurate filling as a benefit to both the provider of the LP gas and to the customer. There is also a need to reduce the amount of time for each filling cycle. The present invention meets these needs by providing a liquid delivery vehicle with a remote control system so that the operator can stand at the storage tank and remotely operate the controls on the truck. This reduces the number of round trips between the delivery vehicle and the storage tank from three to one. Obviously, this saves time and makes the delivery cycle shorter and more efficient. A benefit to the provider of the LP gas is that it allows more deliveries in a given time period and also results in less operator fatigue.
Recently implemented Department of Transportation rules [see 49 C.F.R. .sctn.171.5], require a remotely controlled emergency shut-down, or alternatively, an additional person standing at all times at arm's length from the controls at the truck. The addition of another person at the truck obviously greatly increases labor costs which is not an acceptable alternative in the great majority of cases. The present invention meets the requirements of the regulations by providing a remotely controlled emergency shut-off which substantially simultaneously stops the engine on the vehicle, disengages the power take-off and closes the internal flow valve. In addition to meeting the Department of Transportation regulations, the present invention provides a remote operation of the controls on the vehicle during a typical delivery cycle as described above.